A given wireless communication system typically includes a base transceiver station (BTS) that provides service to one or more mobile stations within the coverage area of the BTS. The BTS may include a radio antenna system having one or more antennas mounted on a tower. A given antenna may transmit downlink signals to and/or receive uplink signals from one or more mobile stations serviced by the BTS. Further, the radio antenna system may also include a tower-top low-noise amplifier (TTLNA) and a feedline system (collectively, a receive signal path), which connects the base station located at the bottom of the tower to various components located at the top of the tower, such as the TTLNA.
It is standard practice to initialize the TTLNA in receive mode. Once the TTLNA has been initialized, the TTLNA will typically operate in either receive mode or in transmit mode. In receive mode, the TTLNA operates to receive signals from the antenna. The TTLNA passes the received signals through a sensitive microwave amplifier to amplify the signals. The amplified signals are then sent to the base station via the feedline system. In transmit mode, the TTLNA receives powerful transmit signals from the base station. In this mode, the sensitive microwave amplifier is bypassed and the powerful transmit signals from the base station are sent to the antenna.
According to current practice, the TTLNA relies on a relatively simple on-off signaling scheme to switch between receive mode and transmit mode. In this signaling scheme, the presence of a control signal causes the TTLNA to switch into transmit mode. And the absence of a signal causes the TTLNA to switch to its default resting state (i.e., receive mode). As an example, the TTLNA may rely on an On-Off-Keying (OOK) signaling scheme. In this signaling scheme, a ground to +5VDC signal transition at the base station initiates a control signal. The control signal is then sent over the feedline system to the TTLNA. The presence of this control signal switches the TTLNA to transmit mode. When the base station transitions its signaling voltage back to ground state, the control signal is terminated. And the absence of the control signal causes the TTLNA to return to is default resting state (i.e., receive mode).